A major structural component in the construction of many buildings is the bearing wall. This is the structure that transfers the vertical acting gravity induced loads generated from roofs and above grade floors to the building foundation. To perform this function acceptably, the wall must neither buckle nor deform vertically to any appreciable degree. The vertical structural elements in the bearing wall, which carry vertical compressive loads, are columnar in nature. These structural elements may be continuous, repetitive and linked, as in diaphragm type structures like reinforced concrete, brick and concrete block, or they may be spaced and discrete as in wood stud, steel stud or timber post type structures
From an economic standpoint, it would be attractive to use baled straw to construct bearing walls. Straw is an inexpensive and readily available renewable resource. Historically, straw has been used in building materials as a binder. Straw bales have been used in building construction as non-structural envelopment components to provide form and thermal and sound insulation. Straw bales have not been widely used in engineered construction primarily because the bales have inherent structural limitations. The basic factor hindering the use of baled straw in construction is its low modulus of elasticity (that is, a flat stress versus strain curve). Considerable deformation has to take place to mobilize the compressive strength of a straw bale. This means that baled straw is not a viable option as a primary structural load bearing element. A wall constructed solely of straw bales performs poorly as a bearing wall because of excessive vertical deformation. This deficiency can be overcome by the insertion of an engineered skeletal framework in the bale matrix. The skeletal framework effectively converts the nature of the bale wall from a linked column type wall structure to a discrete and spaced column type wall structure.